Boron based Lewis acids having fluorinated aryl substituents are known to be capable of activating transition metal compounds into olefin polymerization catalysts. Trisperfluorophenylborane is taught in EP 0 520 732 to be capable of abstracting a ligand for certain cyclopentadienyl derivatives of transition metals while providing a stabilizing, compatible noncoordinating anion. The term "noncoordinating anion" is now accepted terminology in the field of olefin polymerization, both by coordination or insertion polymerization and carbocationic polymerization. See, for example, EP 0 277 004, U.S. Pat. No. 5,198,401, and Baird, Michael C., et al, J. Am. Chem. Soc. 1994, 116, 6435-6436, and U.S. Pat. No. 5,668,324. The noncoordinating anions are described to function as electronic stabilizing cocatalysts, or counterions, for cationic metallocene complexes which are active for olefin polymerization. The term noncoordinating anion as used here applies both to truly noncoordinating anions and coordinating anions that are at most weakly coordinated to the cationic complex so as to be labile to replacement by olefinically or acetylenically unsaturated monomers at the insertion site.
Organoaluminum compounds are known to be useful with metallocene based transition metal cationic catalysts, as cocatalyst activators, or for those stabilized with noncoordinating anions, for both catalyst poison inhibition and alkylation of metallocene dihalide compounds, see WO 91/14713 and EP 0 500 944. See also WO 93/14132 where alumoxane compounds are said to be useful for inhibiting catalyst poisons in the presence of cationic, cyclopentadienyl Group 4 complexes activated by tris(perfluorophenyl)boron.
Certain metallocene compounds having pendant, boron based Lewis acid groups are described by R. E. v. H. Spence and W. E. Piers in "Toward One-Component Group 4 Homogenous Ziegler-Natta Olefin Polymerization Catalysts: Hydroboration of Zirconium bisalkyl with Pendant 2-Propenyl Groups Using [(C.sub.6 F.sub.5).sub.2 BH].sub.2 ", Organomatallics 1995, 14, 4617-4624. As indicated in the title, compounds having boron based Lewis acids having fluorinated aryl substituents linked to cyclopentadienyl ring carbon atoms via hydroboration of propenyl groups that are pendant to cyclopentadienyl ligands are disclosed. It is suggested that these compounds will have utility as zwitterionic, self-activating catalysts. See also the zwitterionic catalysts of U.S. Pat. No. 5,792,819 where pendant, boron based Lewis acid groups are attached to a Group 4 metal center.
The synthesis of Group 13-based compounds derived from trisperfluorophenylborane are described in EP 0 694 548. These compounds are said to be represented by the formula M(C.sub.6 F.sub.5).sub.3 and are prepared by reacting the trisperfluorophenylborane with dialkyl or trialkyl Group 13-based compounds at a molar ratio of "basically 1:1" so as to avoid mixed products, those including the type represented by the formula M(C.sub.6 F.sub.5).sub.n R.sub.3-n, where n=1 or 2. Utility for the trisaryl aluminum compounds in Ziegler-Natta olefin polymerization is suggested.